App creators have taken to Twitter after finding out that their own versions of Flappy Bird have been rejected.

Apple has begun blocking Flappy Bird-style submissions under the grounds that they "leverage a popular app", while Google is labelling Flappy clones simply as "spam".

The apparent policy change does not appear to have affected games already live on app stores - which include titles such as Flappy Fish, Flappy Wings, Flippy Flappy Bird, Floppy Bird and the current top-rated game Fly Birdie - Flappy Bird Flyer.

"There was no 'Fair Warning' email, which Google claims to send before taking such actions," Carpenter continued. "I checked and rechecked my spam folder to be sure. They just arbitrarily removed the app with no warning.

"The message they sent me simply referenced the 'spam' provision of the Google Play terms and did not specifically call out what my transgression was."

Apple and Google's decision to block Flappy Bird clones marks a rare intervention from the companies, who have typically always turned a blind eye to games which don't explicitly break copyright. We've contacted both again this morning to find out what prompted the change.